A method for preparing adiponitrile from butadiene catalyzed by chiral monodentate phosphine ligand

Abstract

The invention discloses a method for preparing adiponitrile from butadiene catalyzed by a chiral monodentate phosphine ligand. Specifically, the method adopts a flow reactor and is completed under a chiral monodentate phosphine ligand, a Lewis acid auxiliary agent and a zero-valent nickel catalytic system. The method of the invention has good selectivity and high conversion rate and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a catalyst system comprising a chiral monodentate phosphine ligand, a Lewis acid and zero-valent nickel, which is used for catalyzing the one-step cyanation of butadiene to prepare adiponitrile. Background Art

[0002] Adiponitrile (molecular formula: NC(CH 2 ) 4 CN, abbreviated as ADN), is a colorless to light yellow transparent liquid with a boiling point of 295°C. It is stable in nature and is mainly used as an intermediate for the manufacture of nylon 66 and as a chromatographic stationary liquid.

[0003] There are many methods for synthesizing adiponitrile. Currently, the main production processes for adiponitrile are acrylonitrile electrolytic dimerization and butadiene method. The butadiene method is mainly divided into two steps: primary cyanidation and secondary cyanidation.

[0004] The main reaction equation can be written as:

[0005]

[0006] In industrial production, the intermediates 3PN and 2M3BN are separated after the first cyanidation of butadiene, of which 2M3BN can be isomerized to obtain 3PN, and 3PN is separated into the product ADN after the second cyanidation. After each cyanidation, it is necessary to recover the unreacted raw materials, catalysts, separate and purify the intermediates and products, and the cyanidation conversion rate and selectivity are very low each time. Usually, the conversion rate of the first cyanidation reaction of butadiene is 70-85%, and the selectivity is 60-75%; the conversion rate of the second cyanidation is 50-72%, and the selectivity is 70-85%. In addition, the two cyanidation reactions require more equipment, which increases the production cost. These reported catalytic systems all have the problems of low conversion rate, low selectivity and unstable catalytic system, so it is necessary to find a better catalyst system.

[0007] CN108997167A (the inventor's existing work) discloses the use of a catalytic system containing a monodentate phosphine ligand containing ferrocene for the one-step cyanation of butadiene to prepare adiponitrile, with an adiponitrile selectivity of 85-95%, which is significantly better than the traditional catalytic system containing a phosphine ligand, with an adiponitrile selectivity of 70-85% (see US3496215 and US3496216). Summary of the invention

[0008] The purpose of the present invention is to provide a catalyst system comprising a chiral monodentate phosphine ligand, a Lewis acid and zero-valent nickel to catalyze the one-step cyanation of butadiene to prepare adiponitrile.

[0009] In a first aspect of the present invention, there is provided a method for preparing adiponitrile from butadiene catalyzed by a chiral monodentate phosphine ligand, comprising the following steps:

[0010]

[0011] (a) providing feed liquid A, feed liquid B and feed liquid C, wherein the feed liquid A is hydrocyanic acid, the feed liquid B is butadiene, and the feed liquid C is a catalyst solution;

[0012] Wherein, the catalyst solution comprises: a chiral monodentate phosphine ligand, a Lewis acid auxiliary agent and zero-valent nickel;

[0013] (b) under a system pressure of 2 to 6 MPa, the liquid A and the liquid B are respectively pumped into a first micro mixer for mixing to obtain a first hot mixed material;

[0014] (c) mixing the first hot mixed material and liquid C in a second micromixer to obtain a second hot mixed material;

[0015] (d) passing the second hot mixed material into a reactor for reaction, thereby obtaining a product liquid containing adiponitrile;

[0016] (e) separating unreacted butadiene and hydrocyanic acid in the product liquid, and separating and treating the remaining material to obtain adiponitrile;

[0017] Wherein, the chiral monodentate phosphine ligand has a structure as shown in Formula I and Formula II:

[0018]

[0019] Wherein, R is selected from the following group: hydrogen, halogen, substituted or unsubstituted C 1 -C 7 Straight chain or branched alkyl, substituted or unsubstituted C 1 -C 7 Straight-chain or branched alkoxy, substituted or unsubstituted phenyl, substituted or unsubstituted benzyl; wherein the substituent is selected from the following group: halogen, C 1 -C 4 Alkyl, diphenylphosphine substituent; Ar 1 and Ar 2 is a substituted or unsubstituted phenyl group, wherein the substituent is selected from the group consisting of halogen, substituted or unsubstituted C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, wherein the substitution is halogen.

[0020] In another preferred embodiment, the liquid B contains nitrogen at a pressure of 0.1-1 MPa.

[0021] In another preferred embodiment, the butadiene is in liquid state.

[0022] In another preferred embodiment, in the step (b), the system pressure is adjusted by a back pressure valve so that the system pressure reaches a set range.

[0023] In another preferred embodiment, the step (b) further comprises: preheating the liquid A before pumping it into the first micro mixer.

[0024] In another preferred embodiment, in the step (b), the preheating is performed using a preheater.

[0025] In another preferred embodiment, the step (c) further comprises: preheating the material C before mixing.

[0026] In another preferred embodiment, in the step (c), the preheating is performed using a heat exchanger.

[0027] In another preferred embodiment, in step (d), the reactor is a shell-and-tube reactor.

[0028] In another preferred embodiment, in step (e), the separation treatment is fractional distillation in a rectification tower.

[0029] In another preferred embodiment, the catalyst solution is prepared and used immediately.

[0030] In another preferred embodiment, in the catalyst solution, the molar ratio of the chiral monodentate phosphine ligand, the Lewis acid auxiliary and the zero-valent nickel is 5-100:0.1-5:1.

[0031] In another preferred embodiment, in the catalyst solution, the molar ratio of the chiral monodentate phosphine ligand, the Lewis acid auxiliary and the zero-valent nickel is 8-50:2-5:1.

[0032] In another preferred embodiment, in the catalyst solution, the molar ratio of the chiral monodentate phosphine ligand, the Lewis acid auxiliary and the zero-valent nickel is 8-30:2-5:1.

[0033] In another preferred embodiment, the R is selected from the following group: hydrogen, C 1 -C 4 Straight or branched alkyl, C 1 -C 4 Straight-chain or branched alkoxy, phenyl, benzyl, 2-diphenylphosphinophenyl, or trifluoromethyl.

[0034] In another preferred embodiment, the R is selected from the following group: tert-butyl, benzyl, phenyl, or trifluoromethyl.

[0035] In another preferred embodiment, the Ar 1 and Ar 2 Same or different.

[0036] In another preferred embodiment, the Ar 1 and Ar 2 is a substituted or unsubstituted phenyl group, wherein the substituent is selected from the following group: a substituted or unsubstituted C 1 -C 4 Straight or branched alkyl, C 1 -C 4 Straight-chain or branched alkoxy, halogen, wherein the substitution is halogen.

[0037] In another preferred embodiment, the Ar 1 and Ar 2 is a group selected from the group consisting of 3-benzyl, 4-benzyl, 2-methoxyphenyl, 4-methoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3,5-dichlorophenyl, 2-trifluoromethylphenyl, 3-trifluoromethylphenyl, 4-trifluoromethylphenyl or 3,5-ditrifluoromethylphenyl.

[0038] In another preferred embodiment, the phosphine ligand is selected from the following group:

[0039]

[0040] In another preferred embodiment, the phosphine ligand is selected from the following group:

[0041]

[0042] In another preferred embodiment, the Lewis acid additive is selected from the following group: copper chloride, ferric chloride, manganese chloride, titanium trichloride, zinc chloride, zinc bromide, silver acetate, aluminum chloride, or a combination thereof.

[0043] In another preferred embodiment, the Lewis acid adjuvant is selected from the following group: silver acetate, zinc chloride, manganese chloride, copper chloride, aluminum chloride, zinc bromide, or a combination thereof.

[0044] In another preferred embodiment, in the second hot mixed material, the molar ratio of butadiene:hydrocyanic acid:zero-valent nickel is 50-1000:50-2000:1.

[0045] In another preferred embodiment, in the second hot mixed material, the mixing molar ratio of butadiene:hydrocyanic acid:zero-valent nickel is 75-600:150-1200:1.

[0046] In another preferred embodiment, in the second hot mixed material, the molar ratio of butadiene to hydrocyanic acid is 0.8-1.2:1-3.

[0047] In another preferred embodiment, the injection flow rate of the feed liquid A is 0.01-5 L / min; the injection flow rate of the feed liquid B is 0.01-5 L / min; and the injection flow rate of the feed liquid C is 0.001-0.5 L / min.

[0048] In another preferred embodiment, the feed liquid A has an injection flow rate of 0.2-2 L / min, preferably 0.8-0.9 L / min.

[0049] In another preferred embodiment, the feed liquid B has an injection flow rate of 0.2-2 L / min, preferably 0.8-0.9 L / min.

[0050] In another preferred embodiment, the injection flow rate of the feed liquid C is 0.02-0.2 L / min, preferably 0.08-0.09 L / min.

[0051] In another preferred embodiment, the reaction temperature is 40-180°C.

[0052] In another preferred embodiment, the reaction temperature is 90-150°C, preferably 100-140°C.

[0053] In another preferred embodiment, the preheating temperature is 40-180°C.

[0054] In another preferred embodiment, the preheating temperature is 90-150°C, preferably 100-140°C.

[0055] In another preferred embodiment, in step (d), the reaction time is 1 to 60 min.

[0056] In another preferred embodiment, the reaction time is 30-60 min, preferably 40-55 min, and more preferably 45-50 min.

[0057] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. DETAILED DESCRIPTION

[0058] The present invention has been extensively studied and extensively screened to develop a novel method for preparing adiponitrile from butadiene catalyzed by a monodentate chiral phosphine ligand. The process of the present invention is simple, the product conversion rate is high, and the production energy consumption is reduced. On this basis, the present invention is completed.

[0059] The specific implementation of the present invention is as follows:

[0060] Step 1: Increase the system pressure to 2-6MPa through back pressure;

[0061] Step 2: pumping the raw material hydrocyanic acid from the storage tank into the microchannel heat exchanger at a certain flow rate through a feed pump and preheating it to a specific temperature, and then pumping it into the first micro mixer;

[0062] Step 3: pumping liquid butadiene containing 0.5 MPa nitrogen pressure in the raw material from a storage tank into the first micro mixer through a feed pump at a certain flow rate;

[0063] Step 4: mixing hydrocyanic acid and butadiene in a first micromixer to obtain a first hot mixed material;

[0064] Step 5: The catalyst solution is pumped from the storage tank into the microchannel heat exchanger at a certain flow rate through a feed pump and preheated to a specific temperature to obtain a hot catalyst solution, which is then pumped into the second micro mixer;

[0065] Step 6: After the first hot mixed material and the hot catalyst solution are mixed in the second micro mixer, they are placed in a tubular reactor and reacted at a specific temperature for a certain period of time;

[0066] Step 7: After the reaction is completed, the unreacted butadiene and hydrocyanic acid are separated, and the remaining materials are treated to obtain the product adiponitrile.

[0067] Compared with the prior art, the advantages of the present invention are:

[0068] (1) The production process is streamlined. In the cyclooctadiene nickel or nickelocene + Lewis acid + chiral monodentate phosphine ligand catalytic system of the present invention, butadiene and hydrocyanic acid can be successfully prepared into adiponitrile through a one-step catalytic reaction, without the need to separate and isomerize the intermediate products 3PN and 2M3BN;

[0069] (2) The reaction has high selectivity, with the selectivity of the product adiponitrile being high, reaching 86% to 95%, and the conversion rate being high, reaching 75% to 85%;

[0070] (3) The catalyst dosage in the reaction of the present invention is low and the catalytic activity is high, which can effectively save production costs in large-scale industrial production;

[0071] (4) Reduce production energy consumption, and ensure high product purity and excellent quality.

[0072] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0073] Example 1

[0074] Step 1: Increase the system pressure to 2MPa through back pressure;

[0075] Step 2: pumping the raw material hydrocyanic acid from the storage tank into the microchannel heat exchanger at a flow rate of 0.87 mL / min through a feed pump to preheat to 100° C., and then pumping it into the first micro mixer;

[0076] Step 3: pumping liquid butadiene containing 0.5 MPa nitrogen pressure in the raw material from a storage tank into the first micro mixer through a feed pump at a flow rate of 0.78 mL / min;

[0077] Step 4: mixing hydrocyanic acid and butadiene in a first micromixer to obtain a first hot mixed material;

[0078] Step 5: Phosphine ligand (Structural Formula I: R is methoxy, Ar 1 is 3-benzyl, Ar 2 The catalyst system is obtained by mixing silver acetate and zero-valent nickel in a molar ratio of 10:2:1, and the catalyst system is pumped from a storage tank into a microchannel heat exchanger at a flow rate of 0.087 mL / min through a feed pump and preheated to 100° C. to obtain a hot catalyst solution;

[0079] Step 6: After the first hot mixed material and the hot catalyst solution are mixed in the second micro mixer, they enter the tube-in-tube reactor and react at 100° C. for 40 minutes, and the mixing molar ratio of butadiene: hydrocyanic acid: zero-valent nickel is 155:300:1;

[0080] Step 7: After the reaction is completed, the unreacted butadiene and hydrocyanic acid are separated, and the remaining materials are treated to obtain adiponitrile.

[0081] In this embodiment, the raw material conversion rate is 80%, the selectivity of the product adiponitrile is 90%, and the crude product is purified by distillation to obtain adiponitrile with a purity of 99.5%.

[0082] Embodiment 2-5

[0083] The operation steps refer to Example 1, and the ligand structure, composition ratio, environmental conditions and various parameters are detailed in the following table:

[0084]

[0085]

[0086]

[0087] Embodiment 6-10

[0088] The operation steps refer to Example 1, and the ligand structure, composition ratio, environmental conditions and various parameters are detailed in the following table:

[0089]

[0090] Embodiment 11

[0091] Step-by-step synthesis of adiponitrile

[0092] First cyanation reaction: Under nitrogen protection, the phosphine ligand (structural formula I: R is methoxy, Ar 1 is 3-benzyl, Ar 2 7 g of the catalyst system obtained by mixing 3-methoxyphenyl) : silver acetate : zero-valent nickel in a molar ratio of 10:2:1 was added into the autoclave at one time, and the autoclave cover was closed to seal; 21 g of raw material liquid butadiene, 10 g of hydrocyanic acid, and 100 mL of anhydrous toluene were sequentially introduced into the autoclave through a metering pump, and the autoclave was sealed and stirred; the reactor was heated to 100° C. and reacted for 3 hours; the temperature was lowered, and samples were taken through a sampling tube for analysis and detection, and the raw material conversion rate was 89.6%, and the selectivity of 3PN was 95.5%.

[0093] Second cyanation reaction: the phosphine ligand (structural formula I: R is methoxy, Ar 1 is 3-benzyl, Ar 2 7 g of the catalyst system obtained by mixing 2-(3-methoxyphenyl)-3-(3-methoxyphenyl)-silver acetate-zero-valent nickel in a molar ratio of 10:2:1 was introduced into the reactor for the first cyanation reaction through a metering pump, and then 10 g of hydrocyanic acid was also introduced into the reactor through a metering pump, and stirring was started; the reactor was heated to 100° C. and reacted for 2 hours; the temperature was lowered, the residual hydrocyanic acid was extracted, and the reaction liquid was subjected to reduced pressure distillation and rectification to obtain the product.

[0094] In this embodiment, the raw material conversion rate is 73.5%, the selectivity of the product adiponitrile is 81.2%, and the crude product is distilled and purified to obtain adiponitrile with a purity of 99.5%.

[0095] Since the catalyst of the present invention can achieve excellent raw material conversion rate in the first step, the reaction of the first step and the second step can be completed in the same system. In addition, it is found through the above examples that compared with the two-step synthesis method of adiponitrile, the one-step synthesis method of adiponitrile can achieve the same or even better raw material conversion rate and selectivity of the product adiponitrile; and there is no need to purify the intermediate, reducing the loss; in addition, the one-step synthesis method of adiponitrile uses less raw materials and catalysts, lower energy consumption, and shorter time, so it has more advantages.

[0096] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference individually. In addition, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing adiponitrile from butadiene catalyzed by a chiral monodentate phosphine ligand, It is characterized in that The steps include: (a) providing feed liquid A, feed liquid B and feed liquid C, wherein the feed liquid A is hydrocyanic acid, the feed liquid B is butadiene, and the feed liquid C is a catalyst solution; Wherein, the catalyst solution comprises: a chiral monodentate phosphine ligand, a Lewis acid auxiliary and zero-valent nickel; (b) under a system pressure of 2 to 6 MPa, the feed liquid A and the feed liquid B are respectively pumped into a first micro mixer for mixing to obtain a first hot mixed material; (c) mixing the first hot mixed material and liquid C in a second micromixer to obtain a second hot mixed material; (d) passing the second hot mixed material into a reactor for reaction, thereby obtaining a product liquid containing adiponitrile; (e) separating unreacted butadiene and hydrocyanic acid in the product liquid, and separating and treating the remaining material to obtain adiponitrile; Wherein, the Lewis acid auxiliary agent is selected from the following group: copper chloride, ferric chloride, manganese chloride, titanium trichloride, zinc chloride, zinc bromide, silver acetate, aluminum chloride, or a combination thereof; Wherein, the chiral monodentate phosphine ligand has a structure as shown in Formula I and Formula II: Wherein, R is selected from the following group: C 1 -C 4 Straight or branched alkyl, C 1 -C 4 Straight-chain or branched alkoxy, phenyl, benzyl, or trifluoromethyl; Ar 1 and Ar 2 is a substituted or unsubstituted phenyl group, wherein the substituent is selected from the group consisting of halogen, halogenated or unsubstituted C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy.

2. The method according to claim 1, characterized in that in the catalyst solution, the molar ratio of the chiral monodentate phosphine ligand, the Lewis acid auxiliary and the zero-valent nickel is (5-100):(0.1-5):

1.

3. The method according to claim 1, It is characterized in that The Ar 1 and Ar 2 is a group selected from the group consisting of 3-methylphenyl, 4-methylphenyl, 2-methoxyphenyl, 4-methoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3,5-dichlorophenyl, 2-trifluoromethylphenyl, 3-trifluoromethylphenyl, 4-trifluoromethylphenyl or 3,5-ditrifluoromethylphenyl.

4. The method according to claim 1, It is characterized in that The phosphine ligand is selected from the following group:

5. The method according to claim 1, It is characterized in that The phosphine ligand is selected from the following group:

6. The method according to claim 1, It is characterized in that The Lewis acid adjuvant is selected from the following group: manganese chloride, zinc chloride, zinc bromide, silver acetate, aluminum chloride, or a combination thereof.

7. The method according to claim 1, It is characterized in that In the second hot mixed material, the molar ratio of butadiene:hydrocyanic acid:zero-valent nickel is (50-1000):(50-2000):

1.

8. The method according to claim 1, It is characterized in that In the second hot mixed material, the molar ratio of butadiene to hydrocyanic acid is (0.8-1.2):(1-3).

9. The method according to claim 1, It is characterized in that The injection flow rate of the feed liquid A is 0.01-5 L / min; the injection flow rate of the feed liquid B is 0.01-5 L / min; the injection flow rate of the feed liquid C is 0.001-0.5 L / min.

10. The method according to claim 1, It is characterized in that The reaction temperature is 40-180°C.

11. The method according to claim 1, It is characterized in that In step (d), the reaction time is 1 to 60 minutes.

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